The purpose of this study is to analyze the influence of institutional ownership and financial performance on sustainable finance practices in energy sector companies listed on the Indonesia Stock Exchange (IDX) for the 2021–2023 period. The study uses a quantitative approach with secondary data obtained from annual reports, sustainability reports, and financial statements. The research sample was selected using purposive sampling techniques, covering 35 companies with a total of 105 observations. Data were analyzed using descriptive statistics, convergent validity tests, convergent validity, convergent validity, inner model and hypothesis testing by data analysis using SEM-PLS based on the SmartPLS 4.0 application. The results show that institutional ownership has a positive effect on sustainable financial practices, while financial performance has no effect. These findings reinforce the Sustainability Maturity Model theory that sustainability maturity is more influenced by governance drives and strategic orientation than simply financial capacity.